Robert Joseph Evans created MAPREDUCE-4301:
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Summary: Dedupe some strings in MRAM for memory savings
Key: MAPREDUCE-4301
URL: https://issues.apache.org/jira/browse/MAPREDUCE-4301
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: applicationmaster
Affects Versions: 2.0.0-alpha, 0.23.3
Reporter: Robert Joseph Evans
Assignee: Robert Joseph Evans
Recently an OutOfMemoryError caused one of our jobs to become a zombie
(MAPREDUCE-4300). It was a rather large job with 78000+ map tasks and only
750MB of heap configured. I took a heap dump to see if there were any obvious
memory leaks, and I could not find any, but yourkit and some digging found some
potential memory optimizations that we could do.
In this particular case we could save about 20MB if
SplitMetaInfoReader.readSplitMetaInfo only computed the JobSplitFile once
instead of for each split. (a 2 line change)
I will look into some others and see if there are more savings I can come up
with.
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